The proposed study is an investigation of how older people cope with the onset of one of several chronic diseases: hypertension, diabetes mellitus, one of several forms of blood cancer (chronic lymphoma, multiple myeloma, chronic lymphocytic leukemia), and rheumatoid arthritis. Strategies of coping with illness onset to be considered include: health behaviors aimed at mastering the demands of illness, and intrapsychic and affiliative behaviors aimed at mastering the distress of being ill. Basic research objectives include: (1) a description of overt and intrapsychic activities employed in the process of coping, (2) a determination of those coping strategies which are effective in maintaining the individual's sense of well-being and sustaining a positive self-concept and appropriate level of physical functioning, and (3) a delineation of the interaction of personality and situational factors which determines what coping strategies are used by the older person. Data will be obtained through interviews with older people randomly selected from among those patients diagnosed as having hypertension, diabetes mellitus, one of several forms of blood cancer (as noted above), or rheumatoid arthritis as their primary health problem. Respondents will be interviewed between one month and one year after illness onset and follow-up data on the disease course will be obtained throughout the following year.